Conventionally, when manufacturing a semiconductor device, a flat panel display, or the like, various liquid processes such as a cleaning process or an etching process are performed on a substrate such as a semiconductor wafer or a liquid crystal substrate by using a substrate processing apparatus.
For example, in a substrate processing apparatus configured to perform a cleaning process on a substrate, a cleaning liquid is supplied onto the substrate which is being rotated, and a surface of the substrate is cleaned by the cleaning liquid. Thereafter, a rinse liquid is supplied onto the substrate, and the surface of the substrate is rinsed by the rinse liquid. Afterwards, a substitution liquid (e.g., IPA (Isopropyl alcohol)) having higher volatility than that of the processing liquid (here, the rinse liquid (e.g., pure water)) used to process the surface of the substrate is supplied, so that the pure water is substituted with the IPA. Then, by dispersing the IPA outward from the surface of the substrate by a centrifugal force caused by rotation of the substrate while discharging an inert gas (e.g., a nitrogen gas), the surface of the substrate is dried.
In a conventional substrate processing apparatus, an IPA discharge nozzle configured to discharge IPA and a nitrogen gas discharge nozzle configured to discharge a nitrogen gas are provided at a single arm with a gap therebetween. The IPA discharge nozzle is configured to discharge the IPA vertically downward toward substrate, and the nitrogen gas discharge nozzle is also configure to discharge the nitrogen gas vertically downward toward the substrate (see, for example, Patent Document 1).
Further, in the conventional substrate processing apparatus, by moving the arm outward from a position above a central portion of the substrate in one direction while discharging the IPA and the nitrogen gas, the IPA on the substrate is pushed away outward by the nitrogen gas.
Patent Document 1: Japanese Patent Laid-open Publication No. 2010-045389
In the conventional substrate processing apparatus, however, if the gap between the IPA discharge nozzle and the nitrogen gas discharge nozzle becomes larger, the IPA may not be pushed away from the substrate by the nitrogen gas. In such a case, the IPA may remain on the substrate, so that particle generation or damage of a circuit pattern may occur. For this reason, the gap between the IPA discharge nozzle and the nitrogen gas discharge nozzle needs to be narrowed. If the gap therebetween is narrowed, however, the IPA may be dispersed by the nitrogen gas. Thus, a flow rate of the nitrogen gas needs to be reduced, and the IPA discharge nozzle and the nitrogen gas discharge nozzle need to be moved at a low speed. As a result, it would take a long time to dry the substrate, and consumption of the IPA would be increased.
Further, in order to increase the flow rate of the nitrogen gas, the IPA discharge nozzle and the nitrogen gas discharge nozzle may be provided independently and moved in different directions. In such a configuration, however, if the nitrogen gas discharged from the nitrogen gas discharge nozzle passes by an interface between a liquid film of the IPA and a substrate surface from which the IPA is removed, the IPA may not be pushed away from the substrate, so that particles are generated or patterns are damaged. Thus, the nitrogen gas discharge nozzle needs to be moved at a low speed not to pass by the IPA interface. Accordingly, the time taken for drying the substrate may be increased.